From owner-freebsd-questions Thu Jan 23 09:18:37 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id JAA00453 for questions-outgoing; Thu, 23 Jan 1997 09:18:37 -0800 (PST) Received: from post-ofc03.srv.cis.pitt.edu (root@post-ofc03.srv.cis.pitt.edu [136.142.185.39]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id JAA00419 for ; Thu, 23 Jan 1997 09:18:22 -0800 (PST) Received: from local (root@localhost) by post-ofc03.srv.cis.pitt.edu (8.8.4/cispo-2.0.1.7) ID ; Thu, 23 Jan 1997 12:18:17 -0500 (EST) Received: via switchmail; Thu, 23 Jan 1997 12:18:17 -0500 (EST) Received: from pop.srv.cis.pitt.edu via qmail ID ; Thu, 23 Jan 1997 12:17:08 -0500 (EST) Received: from ehdup-i-2.rmt.net.pitt.edu (ehdup-i-2.rmt.net.pitt.edu [136.142.21.172]) by pop.srv.cis.pitt.edu with SMTP (8.8.4/cispop-1.6.1.4) ID ; Thu, 23 Jan 1997 12:17:04 -0500 (EST) Received: by ehdup-i-2.rmt.net.pitt.edu with Microsoft Mail id <01BC0927.31C06C40@ehdup-i-2.rmt.net.pitt.edu>; Thu, 23 Jan 1997 12:16:00 -0500 Message-ID: <01BC0927.31C06C40@ehdup-i-2.rmt.net.pitt.edu> From: John Duncan To: Nadav Eiron Cc: Jen and Luke , "questions@FreeBSD.ORG" Subject: RE: EIDE drives Date: Thu, 23 Jan 1997 12:03:20 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk ---------- From: Doug White[SMTP:dwhite@gdi.uoregon.edu] Sent: Wednesday, January 22, 1997 10:56 AM To: Nadav Eiron Cc: Jen and Luke; questions@FreeBSD.ORG Subject: Re: EIDE drives Here I go trying to understand the difference between EIDE and IDE and screw it up massively. :-) Will someone please fill me in? I don't consider a difference between the two. ---- What I gather on the subject: First and foremost, the ide/eide/ata/ata-2 specifications only truly became specified with ata, and nobody felt the need to follow the specification exactly. Before the ata-2 standard came out, there were vlb card manufacturers and drive makers who wanted to provide a 32-bit bus and a couple of higher clock rates to the drives, so they could write "32-bit" on their boxes, and people would buy them. FreeBSD supports some of these features, such as 32-bit pio multi-block transfers, and the ability to select in the kernel-config whether we want to use these features, and how much we want to transfer. What we don't seem to provide is the selectable clock-rates for the drives. My promise bios starts drives automatically at speed 2, and then the win95 driver steps this speed up to the reccommended setting (or user-defined setting) for the drive. The driver claims, although my drives are old enough to not support it, that the speed can be selected from 0 to 8 (I don't know the relations off-hand) and that the speed can also be selected per the ATA spec. (This, sadly, I also cannot test.) There is actually only a small set of "EIDE" enhanced st506 drivers out for us, so if we just collected the data for them (the air force has a good listing), we should be able to write a config option that loads the correct bits. -John